Ideal and Real Solutions

  An ideal solution is a type of solution that follows Raoult's law, which is a thermodynamic law that describes the behavior of solutio...

 

An ideal solution is a type of solution that follows Raoult's law, which is a thermodynamic law that describes the behavior of solutions. Raoult's law states that the vapor pressure of a component in a solution is proportional to its mole fraction in the solution. In other words, the partial pressure of each component in an ideal solution is directly proportional to its concentration in the solution. An ideal solution is a hypothetical concept and does not exist in reality.

A real solution, on the other hand, is a type of solution that does not follow Raoult's law. This can happen for a variety of reasons, including non-ideal interactions between the molecules of the solvent and solute, and changes in the intermolecular forces between the molecules of the solution. In a real solution, the vapor pressure of a component in the solution is not directly proportional to its concentration in the solution.

The behavior of a solution can be described as ideal or real by comparing the vapor pressures of the components in the solution to the values predicted by Raoult's law. If the actual vapor pressures of the components in the solution match the values predicted by Raoult's law, then the solution is said to be ideal. If the actual vapor pressures deviate from the values predicted by Raoult's law, then the solution is said to be real.

It is important to note that most solutions are real solutions rather than ideal solutions. This is because there are usually intermolecular forces between the solvent and solute that cause deviations from Raoult's law. For example, in a solution of water and ethanol, the hydrogen bonding between the molecules of water and ethanol leads to deviations from Raoult's law.

In conclusion, ideal solutions are hypothetical solutions that follow Raoult's law, while real solutions are actual solutions that do not follow Raoult's law. Most solutions are real solutions because of intermolecular forces between the solvent and solute. Understanding the behavior of solutions is important in many fields, including chemistry, physics, and engineering.

Property	Ideal Solution	Real Solution
Vapor pressure	Follows Raoult's law	Deviates from Raoult's law
Interactions between molecules	Molecules of solvent and solute interact ideally	Molecules of solvent and solute interact non-ideally
Enthalpy of mixing	Zero	May be positive or negative
Heat of vaporization	Follows Raoult's law	Deviates from Raoult's law
Boiling point elevation	Follows Raoult's law	Deviates from Raoult's law
Freezing point depression	Follows Raoult's law	Deviates from Raoult's law
Composition of the solution	Determined by mole fraction	May not be determined by mole fraction